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Short answer: King trumpet mushrooms (Pleurotus eryngii), also called king oyster mushrooms, are large edible mushrooms with thick, meaty white stems and small brown caps. A 3-ounce (85 g) serving of raw king trumpet has under 40 calories and provides about 34% of the Daily Value for niacin and 31% for biotin, plus fiber. They are also one of the richer food sources of ergothioneine in USDA testing. Research on their health effects in people is limited: one small study found that a meal with king trumpet led to a smaller rise in blood sugar and more fullness than a matched meal without it.
King trumpet mushrooms have become a grocery store staple, thanks to their firm, chewy texture and mild, savory flavor that holds up to searing, grilling and roasting. Here is what king trumpet mushrooms are, their nutrition, what the research does and does not show about their benefits, and how to cook them.
What you'll learn
- What king trumpet mushrooms are and their other names
- King trumpet nutrition facts, and how they compare with other mushrooms
- What the research shows about king trumpet mushroom benefits
- Side effects and who should be careful
- How to choose, store and cook them
What are king trumpet mushrooms?
King trumpet (Pleurotus eryngii) is an edible mushroom native to Europe, the Middle East and North Africa that is also grown in parts of Asia (Han et al., 2011). It belongs to the same genus as the oyster mushroom (Okuda et al., 2012), which is why it is often sold as the king oyster mushroom. You may also see it labeled eryngii or eringi.
Unlike most mushrooms, most of what you eat is the stem: a thick, white, dense stalk topped by a small tan-brown cap. The flavor is mild and savory, and the texture is firm and chewy, which is why king trumpet is often sliced into rounds and seared like scallops or shredded as a plant-based stand-in for pulled meat.
King trumpet mushroom nutrition facts
Approximate nutrition in a 3-ounce (85 g) serving of raw king trumpet mushrooms, from USDA FoodData Central, with the percentage of the Daily Value (FDA):
| Nutrient | Per 85 g, raw | % Daily Value |
|---|---|---|
| Calories | 32 to 39 kcal* | - |
| Protein | 2.0 g | - |
| Fiber | 2.5 g | 9% |
| Niacin (vitamin B3) | 5.5 mg | 34% |
| Biotin | 9.2 mcg | 31% |
| Riboflavin (vitamin B2) | 0.21 mg | 16% |
| Phosphorus | 76 mg | 6% |
| Vitamin B6 | 0.10 mg | 6% |
| Zinc | 0.54 mg | 5% |
| Potassium | 250 mg | 5% |
*USDA lists two calorie values, 46 or 38 kcal per 100 g, depending on the calculation method.
King trumpets are mostly water (88%) and low in calories. They are a good source of niacin and biotin, with about 34% and 31% of the Daily Value per serving, and provide some fiber and riboflavin. Unlike shiitake, they are not a significant source of copper or selenium, and they have almost no vitamin D: about 0.07 mcg per 100 g (USDA FoodData Central).
How king trumpet compares with other mushrooms
USDA has analyzed several common mushrooms with the same methods. Per 100 g raw (USDA FoodData Central):
| Mushroom | Calories | Fiber | Niacin | Ergothioneine | Beta-glucan |
|---|---|---|---|---|---|
| King trumpet (king oyster) | 46 kcal | 3.0 g | 6.5 mg | 24 mg | 2.0 g |
| Oyster | 41 kcal | 2.8 g | 5.8 mg | 14 mg | 1.9 g |
| Shiitake | 44 kcal | 4.2 g | 2.7 mg | 11 mg | 2.9 g |
| Lion's mane | 43 kcal | 4.4 g | 1.6 mg | 17 mg | 2.8 g |
| White button | 31 kcal | 1.7 g | 3.9 mg | 4 mg | 0.8 g |
Two things stand out. King trumpet has more niacin than most of the others, and of the 11 fresh mushrooms in USDA's Foundation Foods data, it is second only to enoki (26 mg per 100 g) in ergothioneine. Levels vary a lot between batches: across the king trumpet samples USDA tested, ergothioneine ranged from 12 to 53 mg per 100 g (USDA FoodData Central).
King trumpet mushroom benefits: what the research shows
King trumpet is a nutritious, low-calorie food. Research on specific health effects in people is limited, and most of it is small or done in the lab. Here is what has been studied:
- Nutrients. The clearest benefit is nutritional: few calories, some fiber, and a good amount of niacin and biotin (USDA FoodData Central).
- Blood sugar and fullness after a meal. In a randomized crossover study, 19 adults with obesity and metabolic risk factors ate a meal containing king trumpet and a control meal matched for calories and macronutrients. After the king trumpet meal, their blood sugar rose less, levels of the hunger hormone ghrelin were lower, and they reported feeling less hungry and fuller. Insulin and other gut hormones did not differ (Kleftaki et al., 2022). This was a single-meal study in a small group, so it does not show what happens when you eat king trumpet regularly.
- Gut bacteria. In a lab study using stool samples from 8 older adults, mushrooms rich in beta-glucans, including king trumpet, shifted gut bacteria and the short-chain fatty acids they produce (Mitsou et al., 2020). This was done in test tubes, not in people.
- Ergothioneine. Ergothioneine is a compound made by fungi and some bacteria that the human body absorbs through a dedicated transporter and keeps for weeks or months. It is often called an antioxidant, but researchers note that evidence for that role inside the body is still weak (Halliwell et al., 2023). Its role in human health is an active area of research.
Lab and animal studies of king trumpet extracts have looked at immune and allergy-related activity, but those use concentrated extracts rather than the mushrooms you cook, and they do not show effects in people. For a broader look at mushrooms and their evidence, see what the evidence says about functional mushrooms.
Side effects and who should be careful
Cooked king trumpet is a common food that most people eat without problems. A few things to know:
- Mushroom allergy. If you are allergic to other mushrooms, especially oyster mushrooms, talk to an allergist before trying king trumpet.
- Spores and mushroom growers. Large amounts of airborne spores can cause allergic reactions during cultivation (Okuda et al., 2012). Hypersensitivity pneumonitis, an allergic lung reaction, has been reported in a worker at a king trumpet mushroom factory (Saikai et al., 2002). This is an occupational risk, not a risk from eating the mushrooms.
- Digestive comfort. Like other mushrooms, king trumpets contain fiber and beta-glucans (USDA FoodData Central). If you are not used to eating much fiber, start with a modest portion.
- Supplements. King trumpet extracts and mushroom blends are different from the cooked mushroom. If you are pregnant or breastfeeding, take medication or have a medical condition, talk to your health care provider before taking a mushroom supplement. See mushroom blend side effects.
How to choose, store and cook king trumpet mushrooms
Choose: look for firm, smooth, creamy-white stems and dry caps, and skip any that are slimy, wrinkled or soft.
Store: keep them unwashed in the refrigerator, in a paper bag or their original package, and use them while they are still firm.
Prepare: wipe off any dirt with a damp cloth or give them a quick rinse and pat dry. Trim the very bottom of the stem. The whole mushroom, cap and stem, is edible.
Ways to cook them:
- Seared "scallops": slice the stems into thick rounds, score the tops in a crosshatch, and sear in a hot pan with a little oil until deeply browned on both sides. Finish with butter, garlic and soy sauce or lemon.
- Roasted or grilled: halve them lengthwise, brush with oil and roast or grill until tender and golden.
- Shredded: pull the stems apart with a fork into thin strands, then pan-fry until crisp for tacos, sandwiches or noodles.
- Stir-fries and soups: slice thinly and add to stir-fries, ramen or hot pot, where they stay pleasantly chewy.
Looking for another meaty mushroom? See how to cook lion's mane mushrooms and our guide to shiitake mushrooms.
King trumpet in supplements and mushroom blends
King trumpet also appears in mushroom powders and blends, including some mushroom matcha products. A blend contains a small amount of each mushroom, and the research above was done on whole mushrooms in a meal, not on blends. To compare products, see how to choose a quality mushroom extract.
Common myths (quick reality check)
Myth: King trumpet and oyster mushrooms are the same thing. Reality: They are close relatives in the same genus, Pleurotus, but different species. King trumpet has a thick, dense stem and a small cap; oyster mushrooms grow in fan-shaped clusters with thin stems.
Myth: Mushrooms are a good source of vitamin D. Reality: King trumpet has almost no vitamin D, about 0.07 mcg per 100 g raw, according to USDA.
Myth: King trumpet mushrooms are proven to lower blood sugar. Reality: One small, single-meal study found a smaller blood sugar rise after a meal with king trumpet. That is promising, but it does not show long-term effects, and king trumpet is not a treatment for any condition.
Frequently asked questions (FAQ)
What are king trumpet mushrooms?
King trumpet (Pleurotus eryngii), also called king oyster mushroom, is an edible mushroom with a thick, meaty white stem and a small brown cap. It is native to Europe, the Middle East and North Africa and is now grown in many countries.
Are king trumpet mushrooms healthy?
Yes. A 3-ounce (85 g) serving of raw king trumpet has under 40 calories and provides about 34% of the Daily Value for niacin and 31% for biotin, plus fiber and riboflavin.
What are the benefits of king trumpet mushrooms?
They are a low-calorie source of niacin, biotin and fiber, and one of the richer mushroom sources of ergothioneine. One small study found a smaller rise in blood sugar and more fullness after a meal with king trumpet, but more research is needed.
Is king trumpet the same as king oyster mushroom?
Yes. King trumpet, king oyster, eryngii and eringi are all names for Pleurotus eryngii.
What do king trumpet mushrooms taste like?
They have a mild, savory flavor and a firm, chewy, meaty texture. When seared, the stems are often compared to scallops.
Can you eat the stem of a king trumpet mushroom?
Yes. The thick stem is the main part people eat. Just trim off the very bottom.
Can you eat king trumpet mushrooms raw?
They are almost always cooked. Cooking brings out their savory flavor and tender, chewy texture.
Related guides
- Shiitake mushrooms: nutrition, benefits and side effects
- Lion's mane mushroom supplement guide
- Reishi mushroom benefits and side effects
- Turkey tail mushroom benefits
- What is cordyceps?
- Mushroom matcha: what it is
Disclaimer and when to seek help
This article is for general education and is not medical advice. These statements have not been evaluated by the Food and Drug Administration. Our products are not intended to diagnose, treat, cure, or prevent any disease. See a health care provider if you have hives, swelling, trouble breathing or other signs of an allergic reaction after eating or handling mushrooms, and talk to your provider before taking a mushroom supplement if you are pregnant or breastfeeding, take medication or have a medical condition.
References
- U.S. Department of Agriculture, Agricultural Research Service. "Mushroom, king oyster" (FDC ID 2003599). FoodData Central, Foundation Foods; also oyster (1999627), shiitake (1999628), lion's mane (1999626), white button (1999629) and enoki (2003600).
- U.S. Food and Drug Administration. "Daily Value on the Nutrition and Supplement Facts Labels."
- Han EH, et al. "Inhibitory effect of Pleurotus eryngii extracts on the activities of allergic mediators in antigen-stimulated mast cells." Food and Chemical Toxicology, 2011;49(6):1416-1425. doi:10.1016/j.fct.2011.03.034
- Okuda Y, et al. "Construction of a genetic linkage map based on amplified fragment length polymorphism markers and development of sequence-tagged site markers for marker-assisted selection of the sporeless trait in the oyster mushroom (Pleurotus eryngii)." Applied and Environmental Microbiology, 2012;78(5):1496-1504. doi:10.1128/AEM.07052-11
- Kleftaki SA, et al. "Pleurotus eryngii improves postprandial glycaemia, hunger and fullness perception, and enhances ghrelin suppression in people with metabolically unhealthy obesity." Pharmacological Research, 2022;175:105979. doi:10.1016/j.phrs.2021.105979
- Mitsou EK, et al. "Effects of rich in β-glucans edible mushrooms on aging gut microbiota characteristics: an in vitro study." Molecules, 2020;25(12):2806. doi:10.3390/molecules25122806
- Halliwell B, Tang RMY, Cheah IK. "Diet-derived antioxidants: the special case of ergothioneine." Annual Review of Food Science and Technology, 2023;14:323-345. doi:10.1146/annurev-food-060822-122236
- Saikai T, et al. "Hypersensitivity pneumonitis induced by the spore of Pleurotus eryngii (Eringi)." Internal Medicine, 2002;41(7):571-573. doi:10.2169/internalmedicine.41.571
